The applicant has developed general synthetic methods for novel polyimidazole ligands. Tri-imidazoles mimic the metal binding system in carbonic anhydrase, while the bis-imidazole carboxylates mimic the metal binding site of carboxypeptidase. The ligands already prepared compare favorably with carbonic anhydrase in their affinity for Co2plus or Ni2plus, but not Zn2plus. He proposes to synthesize other tri-imidazoles and bis-imidazole carboxylates to mimic, and understand, the extraordinary Zn2plus affinity of the enzymes. He also proposes to study the electronic spectra of Co2plus complexes of his novel ligands; spectra of the Co2plus enzymes have been intensively studied. Studies will include complexing reactions in non-aqueous media, in micelles, and with ligands attached to hydropholbic polymers. The ability of Zn2plus complexes of these novel ligands to catalyze typical reactions of carbonic anhydrase will be examined. Such studies will also utilize non-aqueous solvents, micelles, and polymers. Mechanistic studies aimed at detecting bifunctional catalysis by complexed zinc hydroxide, involving expanded metal coordination, will be performed. Studies on carboxypeptidase A will be continued, to check a general mechanism for this enzyme recently proposed by the applicant. Finally, further studies are proposed on a polyfunctional model for carboxypeptidase A which the applicant has recently decribed.